This laboratory has been involved in contributing to the development of a malarial vaccine. To this end we have been characterizing surface antigen genes from Plasmodium falciparum and have been developing a rodent model for vaccine testing. An antigen corresponding to the sporozoite antigens of the human malarias has been identified in a rodent malaria and a rodent model for malaria vaccines has been developed. We have immunized mice against this antigen. We have challenged the immunized mice with malarial parasites and characterized the degree of protection afforded by the vaccination as well as the B- cell and T-cell responses. We have also identified and characterized a major biochemical step in the development of Plasmodium, the stage-dependent ribosome.